Flat flexible circuits are used in a wide variety of applications in the electrical connector art. Generally, a flat flexible circuit includes a flat flexible insulating substrate having a conductive circuit thereon. The circuit may be a plurality of circuit traces deposited on the substrate, or the circuit may be a ground plane laminated to the substrate as described below, or other circuitry is imaginable. Electronic components are mounted on the substrate in electrical conductive coupling arrangements with the circuit material.
One application of flat flexible circuits is in shielded or filtered connectors. In other words, there are a variety of electrical connectors which are termed "filter" connectors, in that electronic components, such as capacitors, are coupled between the terminals of the connector and a ground plate or plane normally mounted to a face of a dielectric housing of the connector. The filters are used to suppress electromagnetic interference and radio frequency interference entering the connector system. Flat flexible circuits may be used as the ground planes in such filtered electrical connectors. In such applications, the electronic components, such as the capacitors, are mounted to a flat flexible insulating substrate which eventually becomes the ground plane of the electrical connector. Such assemblies are fabricated to facilitate mass production of electrical connectors, particularly multi-conductor/terminal connectors. An example of such an application of a flat flexible filter circuit is shown in U.S. Pat. No. 5,141,455, dated Aug. 25, 1992 and assigned to the assignee of this invention.
Heretofore, flat flexible circuits have been manufactured primarily as individual flexible circuit panels. In other words, a flat flexible insulating substrate may be provided in a continuous strip form. The conductive circuit material may be deposited on the substrate strip in discrete areas or sections therealong corresponding to the areas which will comprise the individual flexible circuits. Indexing holes or other cut-out areas also may be formed in the continuous substrate strip. After being prepared for receiving electronic components, the strip is cut into individual or discrete sections corresponding to individual flexible circuit panels. Thereafter, the individual flexible circuit panels are fed to a work station, such as an insertion or assembly machine, whereat the electronic components, such as capacitors, are mounted on the panels. During these handling procedures, the flexible panels may be carried in a more rigid frame, such as a metal frame. The frame may have mechanical or optical coding to dictate to an assembly machine what particular operations or circuit component insertions are to be carried out with respect to the carried panel.
Various problems continue to be encountered in fabricating flat flexible circuits according to the procedures outlined immediately above. In particular, the individual flat flexible circuit panels are very difficult to manipulate and handle. That is why they often are mounted in the more rigid carrying frames. The panels, with or without the frames, are difficult to store and/or package. All of these handling procedures for the individual flexible panels create inefficiency in processing and are not cost effective in fabricating the ultimate product of the flat flexible circuits.
The present invention is directed to solving these problems in a method which involves not only the initial use of a continuous strip of flexible substrate material, but the ultimate product, complete with its electronic components, is carried in continuous seriatim form through the processing steps and even stored on a reel for subsequent processing or use.